Laser induced breakdown spectroscopy (LIBS) is a type of atomic emission spectroscopy which uses a highly energetic laser pulse as the excitation source. The laser pulse generates a high temperature micro-plasma on the surface of the sample. After this excitation, light that is characteristic of the elemental composition of the sample is emitted and analyzed within a spectrometer. LIBS has become a very popular analytical method in view of some of its unique features such as applicability to any type of sample, practically no sample preparation, remote sensing capability, and speed of analysis.
Traditional laser induced breakdown spectroscopy (LIBS) apparatus is based on single-shot lasers or lasers with very low repetition rate of <10 Hz. These lasers suffer from pulse to pulse variation in pulse energy, pulse width, peak power, etc., which induces instability in the intensity and duration of the produced micro-plasmas. This instability limits the capability of traditional LIBS apparatus for performing quantitative analysis of the subject sample. In addition, LIBS is a point measurement technique in which the size of the sample under analysis is typically limited to sub-millimeter (mm) per measurement point. However, samples under measurement generally have various level of non-uniformity. In order to get a consistent measurement result, multiple points on the sample surface need to be measured. Conventionally, this is achieved by mechanically moving the sample in reference to the laser beam or by scanning/deflecting the laser beam using one-dimensional (1-D) or two-dimensional (2-D) mirrors, such as galvanometer mirrors or MEMS mirrors. Sometimes this is combined with a servo focusing mechanism for automatically focusing the laser beam onto various depths on an uneven surface. For traditional LIBS systems, this process is very time-consuming since they can only measure a few measurement points per second due to the low repetition rate of the excitation laser.